Pros-They are gorgeous snakes, great display animals (on par with GTPs as far as I'm concerned) awesome personalities, incrediable feeders...can you tell I'm a bit biased, lol? They are hands down my favorite snakes. I have a Jungle/Diamond cross and 2 Irian Jayas and they are such fun snakes to work with.
Cons-Hard to think of any really, but maybe the fact that you can't be sure what they will look like as adults if you buy babies...you can get an idea from the parents but it is really a roll of the dice. Some turn out amazing, some not so much. My Jungle/Diamond didn't have a speck of yellow on him when he was a baby, but look at him now!
http://i268.photobucket.com/albums/j...ighyellow2.jpg
They can also be nippy as babies...but in my experience they tame down quite easily. Many snakes are like that when young however, so I can't really say that it is a Carpet specific downside.